My 2001 RX300 with 106,000 miles just froze up and we were told we need new engine...?

the oil light came on and we got the oil changed even though it was not due, the light went off for a few miles and then came back on, then it just stopped. We had it towed to the shop and they said it was the sludge problem...but lexus says the warrenty was up in 08...we never new there was a recall and never had a problem before...we always took good care of the car. Is there anything we can do?